Non-syndromic Cleft Palate: An Overview on Human Genetic and Environmental Risk Factors

Exploring polymorphisms in genes encoding growth factors associated with non-syndromic cleft lip with or without cleft palate and tooth agenesis

OBJECTIVE

To evaluate the association between non-syndromic cleft lip with or without cleft palate (NSCL±P) and tooth agenesis (TA), as well as the association of both conditions with polymorphisms in genes encoding growth factors.

METHODOLOGY

This cross-sectional study included children with NSCL±P and a control group of children without NSCL±P. Permanent teeth TA (excluding third molars) was evaluated using panoramic radiographs by a trained examiner. Only TA located outside the cleft was considered in the NSCL±P group. Genetic polymorphisms in Transforming Growth Factor Beta 1 (TGFB1)-rs1800470 and rs4803455-Transforming Growth Factor Beta Receptor 2 (TGFBR2)-rs3087465 and rs764522-Epidermal Growth Factor (EGF)-rs4444903 and rs2237051-and Epidermal Growth Factor Receptor (EGFR)-rs2227983- were genotyped by real-time PCR allele discrimination from buccal cell samples. Associations were tested by uni and multivariable Poisson regression models (5% significance level).

RESULTS

A total of 243 children-127 with NSCL±P (mean age = 8.80±2.14 years) and 116 without NSCL±P (mean age = 8.58±2.03 years) were included. TA was more frequent in the NSCL±P group (23.8%) than in the control group (6.2%) (p<0.01). The EGF rs2237051 was significantly associated with NSCL±P, independently of the other variables (PRa=1.41; p=0.042). Regarding TA, only the cleft presence was associated with a higher prevalence of TA regardless of different variables (PRa=3.70; p=0.001). There was no association between TA and the investigated genetic polymorphisms. When TA and NSCL±P were considered together, a borderline association was observed with rs1800470 in TGFB1 (p=0.06).

CONCLUSION

NSCL±P is associated with TA outside the cleft area. The EGF rs2237051 was associated with NSCL±P. Polymorphisms in genes encoding growth factors are not associated with TA.

Association of MSX1 gene polymorphisms and maxillary lateral incisor agenesis in Non-syndromic cleft lip and/or palate individuals

Background

To investigate the association between MSX1 gene polymorphisms and maxillary lateral incisor agenesis with and without Non Syndromic Cleft lip and palate (NSCL/P) in a South Indian population.

Methods

The study sample was divided into four groups: Group I: Twenty five Cleft lip and palate (NSCL/P) subjects with unilateral/bilateral congenitally missing maxillary lateral incisors, without agenesis of any other permanent teeth, Group II: Twenty five individuals with NSCL/P and a full complement of teeth, Group III: Twenty five non-cleft individuals with unilateral/bilateral congenitally missing maxillary lateral incisors and Control group: Twenty five healthy individuals with normal teeth development and without orofacial defects. MSX1 gene polymorphisms rs12532, rs1042484 and rs11726039 were genotyped by Sanger sequencing method with pre designed primer using ABI 3730 DNA sequencer. Associations were tested using Pearson Chi-square analysis.

Results

The three SNPs, rs12532, rs1042484 and rs11726039 of MSX1 gene exhibited polymorphism. rs12532 was associated with reduced risk of maxillary lateral incisor agenesis in NSCL/P subjects. rs1042484 had significant association with the NSCL/P without maxillary lateral incisor agenesis (full complement of teeth) subjects. rs11726039 showed significant association with NSCL/P with or without maxillary lateral incisor agenesis.

Conclusion

The present study on a South Indian population revealed a significant association between the MSX1 gene polymorphisms and tooth agenesis in NSCL/P subjects. Keywords: MSX1, non syndromic cleft lip and palate, lateral incisor agenesis.

Population-based assessment of major congenital malformations in the United States: smoking risk association

The incidence of congenital malformations (CM) among non-Hispanic White American (NHWA) mothers was reviewed to identify and evaluate the geographic differences in the most frequent CM subtypes associated with smoking and other risk factors. Data on CM were obtained from 150,775 children (2000-2004) from the Centers for Disease Control and Prevention. Risk factors associated with CM development were the mother's age < 21 and > 35 years, body weight gain during pregnancy, anemia, diabetes mellitus, eclampsia (cases of preeclampsia were omitted), smoking, and alcohol use during pregnancy. Among smoking mothers, the most common CM was omphalocele, club foot, cleft lip, and polydactyly. The highest incidences (CM/10,000 births/year) of observed CM in children of smoking mothers were clubfoot, 25.51 cases (Utah), cleft lip, 22.47 (South Dakota), polydactyly, 21.23 (North Dakota), and omphalocele, 13.14 (Montana). The presence of maternal comorbidities, tobacco and alcohol consumption, and their association with other environmental factors can affect the incidence of CM in NHWA mothers. Further comparisons among the American states regarding the overall changes in CM over the last two decades should uncover crucial outcomes in terms of CM and smoking.

Novel insights into palatal shelf elevation dynamics in normal mouse embryos

Development of the embryonic palate requires that the palatal shelves (PS), which extend from maxillary processes, to grow bilaterally and vertically alongside the tongue. This growth continues until embryonic day (E) 13.5, after which the PS elevate above the tongue and adhere, completing the process by E14.5. Current models indicate that this elevation process involves a complex vertical-to-horizontal PS reorientation. While earlier studies have implied that reorientation occurs rapidly, the precise timing has not been resolved. Time-restricted pregnancies with a 1-h resolution showed that in 97% of C57BL/6J embryos, the PS were unelevated at E14.0. However, 6 h later, at E14.25, the PS had completed elevation in 80% of embryos, indicating that the PS elevate in a rapid and constrained timeframe. Interestingly, all E14.25 embryos with unelevated PS (20%) were female, suggesting sex differences in C57BL/6J PS elevation. In FVB/NJ embryos, the elevation window started earlier (E13.875-E14.25), and without any sex differences. An intermediate stage with unilateral PS elevation was frequently observed. Magnetic resonance imaging (MRI) of various stages showed that PS elevation began with posterior bilateral bulges, which then progressed laterally and anteriorly over time. During elevation, we observed increased cell proliferation in the PS lingual region. Within the bulge, cell orientation was tilted towards the tongue, and actomyosin activity was increased, which together may participate in horizontal projection of the bulge. Thus, our data reveal novel insights into rapid dynamic changes during PS elevation, and lay the foundation for future studies of normal and abnormal palatogenesis.

Cleft Palate Induced by Mycophenolate Mofetil Is Associated with miR-4680-3p and let-7c-5p in Human Palate Cells

Background/Objectives: Cleft palate is a birth defect associated with environmental and genetic factors. Disturbance of microRNAs (miRNAs) and exposure to medicinal agents during pregnancy can cause cleft palate. Although an association between medicine-induced cleft palate and miRNAs has been suggested, it remains to be fully elucidated. This study aimed to clarify the molecular mechanism underlying mycophenolate mofetil (MPM)-induced inhibition of cell proliferation and miRNA expression in human embryonic palatal mesenchymal (HEPM) cells. Methods: Cell viability, apoptosis, and cell cycle-related markers were evaluated 48 h after MPM treatment. In addition, miRNA levels and expression of their downstream genes were measured, and a rescue experiment was performed using miR-4680-3p and/or let-7c-5p inhibitors. Results: MPM dose-dependently reduced HEPM cell viability. Additionally, MPM treatment suppressed cyclin-D1, cyclin E1, cyclin-dependent kinase (CDK)-2, and CDK6 expression in HEPM cells. Furthermore, MPM upregulated miR-4680-3p and let-7c-5p expression and downregulated the downstream genes of each miRNA. Moreover, miR-4680-3p and/or let-7c-5p inhibitors alleviated MPM-induced inhibition of cell proliferation. Conclusions: These results suggest that MPM-induced cleft palate is associated with miR-4680-3p and let-7c-5p expression in HEPM cells.

Family History of Nonsyndromic Orofacial Clefts: A Brazilian Multicenter Study

OBJECTIVE

To summarize the evidence on the relationship between hereditary family history and nonsyndromic orofacial clefts (NSOC) in patients from various Brazilian states.

METHODS

This cross-sectional multicenter study was conducted at six specialized orofacial cleft services across different regions of Brazil. The sample consisted of 1899 patients with NSOC, including cleft lip only (NSCLO), cleft palate only (NSCPO), and cleft lip and palate (NSCLP). Data were collected from clinical records between June 2023 and May 2024. Family history was classified as positive or negative, with additional details on the number of affected relatives, degree of kinship, and type of oral cleft. Statistical analysis was performed using SPSS version 27.0, with chi-square tests and z tests to assess associations between variables, and Student's t test to compare the mean number of affected relatives among cleft types.

RESULTS

Of 1899 patients, 52.6% had NSCLP, 24.11% had NSCPO, and 23.27% had NSCLO. NSCLP and NSCLO were more common in males, while NSCPO was more frequent in females. NSCLP and NSCLO showed similar rates of positive family history, whereas NSCPO had significantly fewer cases with hereditary links. Third-degree relatives were the most affected across all groups.

CONCLUSION

NSCLP and NSCLO showed a higher frequency in males and more cases of positive family history compared to NSCPO. Further studies are needed to explore the genetic basis of NSOC, particularly in genetically diverse populations like Brazil.

Polymorphisms and dental age in non-syndromic cleft lip and palate: a cross-sectional study

BACKGROUND

Children with non-syndromic cleft lip with or without palate (CL ± P) may present alterations in dental development. The purpose of this cross-sectional study was to compare the dental age (DA) between children with and without CL ± P, and whether single nucleotide polymorphisms (SNPs) in genes encoding growth factors are associated with DA variations.

METHODS

Children aged between 5 and 14 years with and without CL ± P were recruited to participate in this study. DA was evaluated by calibrated examiners (kappa > 0.80) using the method proposed by Demirjian et al. (1973). Genomic DNA was extracted from buccal cells, and SNPs in Epidermal Growth Factor (EGF) - rs4444903 and rs2237051, Epidermal Growth Factor Receptor (EGFR) - rs2227983 -, Transforming Growth Factor Beta 1 (TGFB1) - rs1800470 and rs4803455 -, and Transforming Growth Factor Beta Receptor 2 (TGFBR2) - rs3087465 - were genotyped by real-time polymerase chain reactions using the TaqMan assay. The Student T-test was used to compare the variations in DA between the phenotypes "with CL ± P" and "without CL ± P", and the ANOVA two-way test was performed to compare the variations in DA among the genotypes (α = 0.05). A post-hoc analysis was performed using Bonferroni correction.

RESULTS

Two hundred and nine (n = 209) children (100 with CL ± P and 109 without CL ± P) with a mean chronological age of 8.66 years - standard deviation (SD) = 1.92 - were included. The group with CL ± P demonstrated a significantly delayed DA (mean=-0.23; SD = 0.71) compared to the group without CL ± P (mean=-0.01; SD = 0.88) (p = 0.049). Genotype distributions were in Hardy-Weinberg equilibrium. The SNP rs4803455 in TGFB1 was significantly associated with DA variations in children without CL ± P (p < 0.01). In the group with CL ± P, no significant differences in DA were observed among the genotypes.

CONCLUSION

Children with CL ± P presented delayed DA compared with children without CL ± P. The SNP rs4803455 in TGFB1 is associated with variations in DA in children without CL ± P.

Experimental study on the preventive effect of Anemarrhena rhizome on pregnancy loss and the incidence rate of cleft palate in A/J mice

Pregnancy loss is a significant concern worldwide, encompassing miscarriage and stillbirth. Miscarriage, defined as the loss of a baby before 28 weeks of gestation, accounts for approximately 15% of pregnancies. Stillbirth, occurring at or after 28 weeks of gestation, affects nearly 2.0 million pregnancies annually, predominantly in low- and middle-income regions. This study aims to investigate the potential of Anemarrhena rhizome (AR) herbal medicine in mitigating pregnancy loss and reducing the incidence of cleft palate in A/J mice models. A total of 390 6-week-old A/J mice were used for the study. Three different dosages of dried AR (6, 12, and 18 g) were boiled to prepare water extracts. The mice were divided into experimental groups receiving these extracts and a control group. Pregnancy outcomes, including fetal mortality rates and incidence of cleft palate, were assessed. The experimental groups receiving AR herbal medicine demonstrated significantly lower fetal mortality rates compared to the control group. Additionally, the incidence of cleft palate was notably reduced in the experimental groups, with the AR 6 g and AR 12 g groups showing significant reductions compared to the control group. AR herbal medicine shows promise in mitigating pregnancy loss and reducing the incidence of cleft palate in A/J mice models. These findings suggest the potential of AR as a therapeutic agent for improving fetal health outcomes. Further research is warranted to elucidate the underlying mechanisms and optimize dosage strategies for maximizing its therapeutic benefits in pregnancy-related complications.

The IRF6 rs2013162 and MTHFR A1298C rs1801131 Gene Polymorphisms Related to non-Syndromic Cleft lip and Palate among Deutero-Malay in Indonesia

OBJECTIVE

This study aimed to identify risk factors for NSCLP by analyzing polymorphisms in IRF6 rs2013162 and MTHFR A1298C rs1801131 in the Deutero Malay Population in Indonesia.

SETTING

DNA isolation from venous blood samples was done followed by PCR and PCR-RFLPs method.

PATIENTS/PARTICIPANTS

115 NSCLP subjects and 120 healthy control subjects.

MAIN OUTCOME MEASURE(S)

The odds ratio (OR) determined to evaluate the risk factors is the main outcome measure.

MATERIAL AND METHODS

The study is a case-control design using samples from the venous blood of 115 NSCLP subjects and 120 healthy control subjects. After DNA was extracted, the PCR-RFLPs method was performed using the DdeI restriction enzyme on 100 blood samples of the IRF6 rs2013162 group and Mboll restriction enzyme on 135 blood samples of the MTHFR A1298C rs1801131 group. The Chi-Square test was used with the Exact Fisher alternatives, depending on the expected count value.

RESULTS

The results showed that the T mutant allele (OR = 4.125, P < .05) and GT genotype (OR = 21.00, P < .05) of IRF6 rs2013162 and the C mutant allele (OR = 3.781, P < .05), AC genotype (OR = 5, P < .05) and CC genotype (OR = 9,681, P < .05) of the MTHFR A1298C is associated to a greater risk of NSCLP.

CONCLUSIONS

IRF6 rs2013162 and MTHFR A1298C rs1801131 gene polymorphisms are strongly associated with NSCLP among the Deutero Malay population in the Indonesian population.

Maternal factors increase risk of orofacial cleft: a meta-analysis

Orofacial clefts are among the most prevalent birth defects, with severe medical and psychosocial consequences. Cleft lip with or without cleft palate (CL ± P) and cleft palate only (CPO) affect on average nearly 1/700 births worldwide. The cause of most non-syndromic cases is unknown. Maternal factors and disorders are assumed to modify the risk of orofacial clefting. In the present study, we performed a systematic review and meta-analysis to analyze the effects of maternal underweight, obesity, hypertension, diabetes, as well as smoking, and alcohol consumption on the development of orofacial clefts. As CL ± CP and CPO have distinct pathogenetic backgrounds, these cleft subtypes were assessed separately. Altogether, 5,830 studies were identified and 64 of them met the inclusion and exclusion criteria. Obesity significantly elevated the odds of clefting (OR = 1.28, CI:1.08-1.51) (ORCL±CP = 1.23, CI:1.01-1.50; ORCPO = 1.31, CI:0.97-1.77). Maternal underweight also significantly increased the odds of clefting (OR = 1.21 CI:1.06-1.38). In mothers with type 1 diabetes, the odds of cleft development were significantly elevated (OR = 1,75, CI:1.45-2.12). Essential hypertension was also associated with higher odds of developing cleft (OR = 1.55, CI:1.18-2.03). Smoking during pregnancy significantly elevated the odds of cleft development (OR = 1.55, CI:1.34-1.79) (ORCL±CP = 1.58, CI:1.36-1.83; ORCPO = 1.50, CI:1.15-1.96). Passive smoking was even more damaging than active tobacco use, but alcohol consumption had no effect. In conclusion, this study clearly showed the importance of maintaining normal maternal body weight and emphasized the importance of hypertension and type 1 diabetes care in the first months of pregnancy. It also highlighted similarnegative effects of passive and active smoking, while alcohol consumption did not seem to be a significant risk factor for cleft development. However, there is a complete lack of available studies on the interactions of these factors, which is an essential direction for improving prevention.

Orofacial Cleft and Its Association with Consanguineous Marriage and Other Risk Factors: A Case-control Study from a Tertiary Care Hospital in Jammu Province

Background

Orofacial cleft is among the most common craniofacial malformations. It presents a complex and multifactorial etiology that involves genetic and environmental factors. One of the etiological factors is consanguinity (marriage between blood relatives). Multiple environmental risk factors, such as advanced maternal age, parity, maternal smoking, radiation, alcohol consumption, diabetes mellitus, and maternal use of drugs (i.e., anticonvulsants), folic acid deficiency, etc., have also been linked to the development of cleft lip and/or palate (CL/P). There is a dearth of literature reporting the occurrence of cleft due to consanguinity and other risk factors.

Aim

The aim of this study is to describe the orofacial cleft demographics and to determine the influence of parental consanguinity and other associated risk factors on the occurrence of orofacial clefts (OFC) at a tertiary healthcare hospital in Jammu Province.

Materials and methods

This was a hospital-based case-control study. In the present study, data collection was specifically done regarding demographic features, history of consanguinity, degree of consanguinity, and other associated maternal risk factors in both the cleft and control groups.

Result

This study elucidates a significant association between parental consanguinity, degree of consanguinity, and other associated risk factors (i.e., maternal age ≥30 years, birth order ≥3, maternal smoking, alcohol consumption, and lack of folic acid consumption) with the occurrence of OFC.

Conclusion

Prevention is better than cure. Awareness programs and appropriate counseling should be conducted to educate the community about the risk factors and the anticipated genetic consequences of consanguinity to prevent the development of cleft anomalies in such populations.

How to cite this article

Gupta A, Kaul B, Gulbar S, et al. Orofacial Cleft and Its Association with Consanguineous Marriage and Other Risk Factors: A Case-control Study from a Tertiary Care Hospital in Jammu Province. Int J Clin Pediatr Dent 2024;17(11):1258-1264.

Cleft lip and palate and periconception COVID-19 infection in five arab countries

BACKGROUND

Little is known about factors associated with the severity of cleft lip with or without cleft palate (CL/P) especially during the COVID-19 pandemic with its dramatic changes.

OBJECTIVES

The aim of this multi-national study is to measure the association between CL/P severity, COVID-19 infection, and fear of COVID-19 in five Arab countries.

METHODS

This cross-sectional study took place in major governmental hospitals in five Arab countries from November 2020 to April 2023. Participants were infants born with CL/P and their mothers who were in their 1st trimester during the COVID-19 pandemic. Clinical examination was carried out, and CL/P cases were grouped according to phenotype: cleft lip and palate (CLP) versus cleft lip (CL), cleft extension (incomplete versus complete), and site (unilateral versus bilateral) to assess severity. Information on maternal COVID-19 infection and fear of COVID-19 were gathered.

RESULTS

The study recruited 273 CL/P infants. Maternal COVID-19 infection during one-month pre-gestation and 1st trimester was significantly associated with higher odds of CL/P severity (AOR = 2.707; P = 0.002) than mothers without the COVID-19 infection. Using supplements during pregnancy showed a protective effect (AOR = 0.573; P = 0.065).

CONCLUSION

Mothers infected with COVID-19 before and during pregnancy had more than twofold higher odds of having an infant with a more severe CL/P phenotype.

A Unique Case Report of Meningeal Hamartoma Within Alveolar Cleft

This case report demonstrates a rare finding of a pediatric patient with Morning Glory anomaly and Moyamoya Disease with a palatal meningeal hamartoma discovered as a mass within a previously repaired incomplete cleft of the alveolus. Oral meningeal hamartomas are exceedingly rare with only two palatal cases described and none within a cleft palate or alveolus. These findings prompt a review of oral hamartomas with meningeal subclassification. Further discussion describes the relationship of the proposed origins of meningeal hamartomas within the setting of cleft palate development.

Comparison of temporomandibular joint osseous components in unilateral and bilateral cleft lip and palate patients and normal controls: A CBCT study

OBJECTIVE

The objective of this study was to conduct a comparative analysis of the components of the temporomandibular joint in individuals with unilateral, bilateral cleft lip and palate (CLP), and in healthy individuals, utilizing cone beam computed tomography (CBCT) images.

METHOD AND MATERIAL

The present study employed a cross-sectional design and recruited participants aged 18 to 30 years. The participants were categorized into three groups: a control group consisting of 36 individuals without any cleft, a group of 35 patients with unilateral cleft lip and palate (UCLP), and a group of 15 patients with bilateral cleft lip and palate (BCLP). The analysis of CBCT images encompassed the examination of condylar height and angulation, glenoid fossa height and width, articular eminence inclination, as well as joint spaces across all three groups. The Kruskal-Wallis and Mann-Whitney tests were employed to ascertain the significant differences among the three groups.

RESULTS

The UCLP and BCLP groups demonstrated a statistically significant reduction in condylar height and articular eminence inclination in comparison to the control group. Furthermore, a significant difference in the width of the glenoid fossa was seen between the group with clefts and the control group.

CONCLUSION

The CBCT images showed significant differences in several aspects of the temporomandibular joint, including condylar height, articular eminence inclination, and glenoid fossa width, in individuals with cleft palate. These abnormalities can contribute to the development of temporomandibular joint diseases. Therefore, recognizing these distinctions can help prevent further deterioration and progression of temporomandibular disorders (TMD) in CLP patients.

The Frequency of Risk Factors for Cleft Lip and Palate in Mexico: A Systematic Review

BACKGROUND

Cleft lip and palate is an anomaly that affects both women and men. It is considered to be among the most frequent congenital abnormalities and is related to modifications in chromosomal DNA and multiple genetic alterations. This anomaly can also be associated with various environmental factors, such as tobacco and alcohol consumption, medication use, and exposure to different environmental and industrial toxic substances. The objective of this study was to document the frequency of risk factors related to cleft lip and palate through a systematic review of Mexican studies.

METHODS

In this systematic review, a bibliographic search was conducted following PRISMA guidelines in the databases Scielo, ScienceDirect, PubMed, and EBSCO. Keywords related to cleft lip and palate, epidemiology, and risk factors were used. In all, 3 independent reviewers (J.A.S.L., S.L.V., and N.M.F.) selected and evaluated a total of 17 articles included in this analysis, achieving a coefficient of κ = 0.84.

RESULTS

The analysis revealed that the highest frequency of conducted studies was in the State of Mexico. The most common risk factors identified were environmental, pharmacological, consumption habits, and gynecological factors.

CONCLUSIONS

Identifying the main risk factors for cleft lip and palate in the Mexican population will enable the implementation of preventive measures aimed at reducing exposure to these factors. Additionally, early intervention can improve the quality of life for individuals affected by this condition.

Genetic associations and parent-of-origin effects of PVRL1 in non-syndromic cleft lip with or without cleft palate across multiple ethnic populations

OBJECTIVES

This study investigated the associations of PVRL1 gene variants with non-syndromic cleft lip with or without cleft palate (NSCL/P) by evaluating transmission distortion and parent-of-origin (POO) effects in multiple ethnic populations.

METHODS

We conducted allelic and genotypic transmission disequilibrium tests (TDT) on 10 single-nucleotide variants (SNVs) in PVRL1 using data from 142 Korean families with an affected child. POO effects were analyzed using the POO likelihood ratio test, comparing transmission rates of maternally and paternally inherited alleles. To assess generalizability and ethnic heterogeneity, we compared results from Korean families with data from the Center for Craniofacial and Dental Genetics, which included 2,226 individuals from 497 European and 245 Asian trios.

RESULTS

TDT analysis identified significant over-transmission of the rs7940667 (G361V) C allele in Korean families (p=0.007), a finding replicated in both Asian (p=6.5×10-7) and European families (p=1.6×10-10). Eight SNVs showed strong TDT evidence in larger Asian and European datasets after multiple comparison corrections (p<0.0073). Of these, 4 SNVs (rs7940667, rs7103685, rs7129848, and rs4409845) showed particularly robust association (p<5×10-8). POO analysis revealed significant maternal over-transmission of the rs10790330-A allele in Korean families (p=0.044). This finding was replicated in European families (p=9.0×10-4). Additionally, 3 other SNVs, rs7129848 (p=0.001) and the linked SNVs rs3935406 and rs10892434 (p=0.025), exhibited maternal over-transmission in the validation datasets.

CONCLUSIONS

Our findings provide robust evidence supporting the associations of PVRL1 variants with NSCL/P susceptibility. Further research is necessary to explore the potential clinical applications of these findings.

Orofacial clefts in Costa Rica, 1996-2021: Analysis of surveillance data

BACKGROUND

Orofacial clefts (OFCs) are among the most common birth defects (BD). In 2008, a series of improvements began in the Costa Rican Birth Defect Register Center (CREC). We aim to explore trends between 1996 and 2021.

METHODS

A trend analysis of OFCs from 1996 to 2021 and a descriptive analysis of OFCs from 2010 to 2021 were performed based on data from the CREC, the national BD surveillance system. Prevalence at birth was calculated according to the type: cleft palate (CP), cleft lip with or without CP (CL ± P), and presentation (isolated, multiple non-syndromic, or syndromes). We used joinpoint regression to identify if a significant change in trend occurred; the average annual percent change (AAPC) was determined. Marginal means and prevalence ratios by subperiod (1996-2009 as referent and 2010-2021) were estimated using Poisson regression and compared using Wald's chi-square tests (α ≤.05).

RESULTS

We found a significant AAPC for OFCs prevalence of +1.4: +0.6 for isolated, +2.9 for multiple non-syndromic, and +7.7 for syndromes (p < .05). When comparing the OFC's prevalence of the subperiod 2010-2021 (11.86 per 10,000) with 1996-2009 (9.36 per 10,000) the prevalence ratio was 1.3 (p < .01): 1.1 (p < .05) for isolated, 1.6 (p < .01) for multiple non-syndromic, and 3.3 (p < .01) for syndromes. The prevalence of OFCs from 2010 to 2021 was 9.1 for CL ± P and 2.8 for CP. Seventy-one percent of the OFCs were isolated, 22% multiple non-syndromic, and 7% syndromes.

CONCLUSION

The trend in OFCs' prevalence is toward increasing, mainly due to improvements in the surveillance system.

Orofacial Clefts and Maternal Risk Factors: A Population-Based Case-Control Study

BACKGROUND/OBJECTIVES

Orofacial clefts (OFCs) are some of the most common congenital anomalies worldwide. The aim of this case-control study was to evaluate the association of OFCs with selected maternal characteristics.

METHODS

Data on isolated non-syndromic cases of OFCs were extracted from the population-based registry of congenital anomalies of Tuscany. A sample of live-born infants without any congenital anomaly was used as the control group. We investigated the association with sex and some maternal characteristics: age, body mass index, smoking, and education. Adjusted odds ratios (OR) were calculated using a logistic regression model. Analyses were performed for the total OFCs and separately for cleft lip (CL) and cleft palate (CP).

RESULTS

Data on 219 cases and 37,988 controls were analyzed. A higher proportion of males (57.9%) was observed, particularly for CL. A decreasing trend among the maternal age classes was observed (OR:0.81 (95%CI 0.70-0.94)). Underweight mothers had a higher prevalence of OFCs, in particular for CL (OR:1.88 (95%CI 1.08-3.26)).

CONCLUSIONS

We found an association of OFCs with lower maternal age. The association with maternal age remains controversial and further epidemiological evidence is needed through multicenter studies. We observed that CL was more common in underweight mothers, suggesting actions of primary prevention.

The heterogeneous genetic architectures of orofacial clefts

Orofacial clefts (OFCs) are common, affecting 1:1000 live births. OFCs occur across a phenotypic spectrum - including cleft lip (CL), cleft lip and palate (CLP), or cleft palate (CP) - and can be further subdivided based on laterality, severity, or specific structures affected. Herein we review what is known about the genetic architecture underlying each of these subtypes, considering both shared and subtype-specific risks. While there are more known genetic similarities between CL and CLP than CP, recent research supports both shared and subtype-specific genetic risk factors within and between phenotypic classifications of OFCs. Larger sample sizes and deeper phenotyping data will be of increasing importance for the discovery of novel genetic risk factors for OFCs and various subtypes going forward.

A common cis-regulatory variant impacts normal-range and disease-associated human facial shape through regulation of PKDCC during chondrogenesis

Genome-wide association studies (GWAS) identified thousands of genetic variants linked to phenotypic traits and disease risk. However, mechanistic understanding of how GWAS variants influence complex morphological traits and can, in certain cases, simultaneously confer normal-range phenotypic variation and disease predisposition, is still largely lacking. Here, we focus on rs6740960, a single nucleotide polymorphism (SNP) at the 2p21 locus, which in GWAS studies has been associated both with normal-range variation in jaw shape and with an increased risk of non-syndromic orofacial clefting. Using in vitro derived embryonic cell types relevant for human facial morphogenesis, we show that this SNP resides in an enhancer that regulates chondrocytic expression of PKDCC - a gene encoding a tyrosine kinase involved in chondrogenesis and skeletal development. In agreement, we demonstrate that the rs6740960 SNP is sufficient to confer chondrocyte-specific differences in PKDCC expression. By deploying dense landmark morphometric analysis of skull elements in mice, we show that changes in Pkdcc dosage are associated with quantitative changes in the maxilla, mandible, and palatine bone shape that are concordant with the facial phenotypes and disease predisposition seen in humans. We further demonstrate that the frequency of the rs6740960 variant strongly deviated among different human populations, and that the activity of its cognate enhancer diverged in hominids. Our study provides a mechanistic explanation of how a common SNP can mediate normal-range and disease-associated morphological variation, with implications for the evolution of human facial features.

Let-7c-5p associate with inhibition of phenobarbital-induced cell proliferation in human palate cells

Cleft palate (CP) is one of the most common congenital diseases, and is accompanied by a complicated etiology. Medical exposure in women is among one of the reasons leading to CP. Recently, it has been reported that microRNA (miRNA) plays a crucial role in palate formation and the disruption of miRNA that influence the development of CP. Although association with pharmaceuticals and miRNAs were suggested, it has remained largely unknow. The aim of the current investigation is to elucidate upon the miRNA associated with the inhibition of phenobarbital (PB)-induced cell proliferation in human embryonic palatal mesenchymal (HEPM) cells. We showed that PB inhibited HEPM cell viability in a dose-dependent manner. We demonstrated that PB treatment suppressed cyclin-D1 expression in HEPM cells. Furthermore, PB upregulated let-7c-5p expression and downregulated the expression of two downstream genes (BACH1 and PAX3). Finally, we demonstrated that the let-7c-5p inhibitor alleviated PB-induced inhibition of cell proliferation and altered BACH1 and PAX3 expression levels. These results suggest that PB suppresses cell viability by modulating let-7c-5p expression.

Bioglass 45S5, a relevant alternative to autogenous harvesting for secondary alveolar bone grafts in clefts? Retrospective study of one hundred surgeries

The secondary alveolar bone grafting (SABG) step restores the continuity of the alveolar bone necessary for dentition. Faced with the complications of autografts, synthetic biomaterials such as Bioglass (BG) 45S5 have been proposed. The objective was to evaluate the success rate of SABG with the addition of BG 45S5 and to highlight the prognostic factors. Patients who underwent operation between 2015 and 2021 and had follow-up cone-beam computed tomography (CBCT) were analyzed. Multivariate analysis was performed to determine factors influencing radiographic success. A total of 102 SABG were analyzed. They were unilateral total cleft lip and palate (49, 48.0%). The mean age at surgery was 9.32 ± 3.09 years. Surgeries were performed mainly outside a syndromic context and without a family history after orthodontic preparation. The radiographic success rate at 1 year was 80.4%. Mixed dentition stage (odds ratio [OR] = 7.3, p = 0.024), absence of syndromic context (OR = 20.7, p = 0.024) and female sex (OR = 4.88, p = 0.021) were factors predictive of surgical success. The use of BG 45S5 instead of autograft is relevant for SABG, with a 1-year success rate of over 80%. The stage of mixed dentition, the absence of syndromic context, and female sex were factors for good prognosis.

Involvement of microRNA-4680-3p against phenytoin-induced cell proliferation inhibition in human palate cells

Cleft palate (CP) is one of the most common birth defects and is caused by a combination of genetic and/or environmental factors. Environmental factors such as pharmaceutical exposure in pregnant women are known to induce CP. Recently, microRNA (miRNA) was found to be affected by environmental factors. The aim of the present study was to investigate the involvement of miRNA against phenytoin (PHE)-induced inhibition of proliferation in human embryonic palatal mesenchymal (HEPM) cells. We demonstrated that PHE inhibited HEPM cell proliferation in a dose-dependent manner. We found that treatment with PHE downregulated cyclin-D1 and cyclin-E expressions in HEPM cells. Furthermore, PHE increased miR-4680-3p expression and decreased two downstream genes (ERBB2 and JADE1). Importantly, an miR-4680-3p-specific inhibitor restored HEPM cell proliferation and altered expression of ERBB2 and JADE1 in cells treated with PHE. These results suggest that PHE suppresses cell proliferation via modulation of miR-4680-3p expression.

How are people with orofacial clefts attended in northwest region of São Paulo state, Brazil?

Characterization of specific birth defects is essential for conducting scientific investigations, care and therapeutic strategies. This article describes demographic, clinical and genetic aspects, risk factors and access to treatment of Brazilian patients with orofacial clefts registered in a specialized collaborative center of the Brazilian Database on Craniofacial Anomalies (BDCA). We interviewed 70 individuals with typical orofacial clefts using a standard instrument from the database and subjected them to genetic testing. The patients were grouped as syndromic and non-syndromic. The majority of individuals were of lower middle class, native ancestry and syndromic. There was a significant difference in the type of clefts regarding gender. There was no significant difference between bilateral and unilateral, between the side affected, right and left, or familial recurrence related to type of oral cleft. The risk factor familial recurrence was significantly higher among non-syndromic cases. Etiological factors were identified or suggested in 62.5% of the syndromic cases. There was a delay in diagnosis and in access to treatment in most cases. We concluded that gender, native ancestry and low family income represent risk factors. Furthermore, the distribution by cleft types and gender is similar to previous studies. The results can guide scientific investigations and care policies.

A Rare Case of Cleft Palate Associated With Tongue Hamartoma: A Case Report and Systematic Review

INTRODUCTION

Palate development involves a genetic regulation through a complex molecular mechanism that may be disrupted by environmental factors, resulting in impaired fusion and cleft palate formation. An encounter with a case of cleft palate due to dorsal tongue hamartoma prompted us to perform this systematic review.

OBJECTIVE

To review the clinical profile and management approach for a case with cleft palate and tongue hamartoma.

DESIGN

A systematic literature search was conducted using keywords related to cleft palate and tongue hamartoma in PubMed, Scopus, MEDLINE, and Scielo databases through December 2021, with no time or language restrictions.

PATIENTS, PARTICIPANTS

Studies reporting patients with cleft palate and tongue hamartoma were included.

MAIN OUTCOME MEASURE(S)

Information related to clinical profile, diagnostic tests, histopathology, management, and outcomes were extracted.

Fourteen relevant publications were identified with 16 cases reported so far. Among them, thirteen patients were females (81.25%), and 3 were males (18.75%). The age of presentation varied from birth to 19 years. Oral-facial-digital syndrome (type II) was the most commonly associated syndrome.

Congenital tongue hamartoma with cleft palate is a rare presentation, which can present as an isolated entity or part of a syndrome. Genetic evaluation is warranted, particularly for multiple hamartomatous lesions. The preferred treatment is immediate excision of hamartoma while following a standard timeline for palatoplasty.

RA-induced prominence-specific response resulted in distinctive regulation of Wnt and osteogenesis

Proper retinoic acid (RA) signaling is essential for normal craniofacial development. Both excessive RA and RA deficiency in early embryonic stage may lead to a variety of craniofacial malformations, for example, cleft palate, which have been investigated extensively. Dysregulated Wnt and Shh signaling were shown to underlie the pathogenesis of RA-induced craniofacial defects. In our present study, we showed a spatiotemporal-specific effect of RA signaling in regulating early development of facial prominences. Although inhibited Wnt activities was observed in E12.5/E13.5 mouse palatal shelves, early exposure of excessive RA induced Wnt signaling and Wnt-related gene expression in E11.5/E12.5 mouse embryonic frontonasal/maxillary processes. A conserved regulatory network of miR-484-Fzd5 was identified to play critical roles in RA-regulated craniofacial development using RNA-seq. In addition, subsequent osteogenic/chondrogenic differentiation were differentially regulated in discrete mouse embryonic facial prominences in response to early RA induction, demonstrated using both in vitro and in vivo analyses.

An improved multicellular human organoid model for the study of chemical effects on palatal fusion

BACKGROUND

Tissue fusion is a mechanism involved in the development of the heart, iris, genital tubercle, neural tube, and palate during embryogenesis. Failed fusion of the palatal shelves could result in cleft palate (CP), a common birth defect. Organotypic models constructed of human cells offer an opportunity to investigate developmental processes in the human. Previously, our laboratory developed an organoid model of the human palate that contains human mesenchyme and epithelial progenitor cells to study the effects of chemicals on fusion.

METHODS

Here, we developed an organoid model more representative of the embryonic palate that includes three cell types: mesenchyme, endothelial, and epithelial cells. We measured fusion by a decrease in epithelial cells at the contact point between the organoids and compared the effects of CP teratogens on fusion and toxicity in the previous and current organoid models. We further tested additional suspect teratogens in our new model.

RESULTS

We found that the three-cell-type model is more sensitive to fusion inhibition by valproic acid and inhibitors of FGF, BMP, and TGFβRI/II. In this new model, we tested other suspect CP teratogens and found that nocodazole, topiramate, and Y27632 inhibit fusion at concentrations that do not induce toxicity.

CONCLUSION

This sensitive human three-cell-type organotypic model accurately evaluates chemicals for cleft palate teratogenicity.

Advances in research of biological functions of Isthmin-1

Isthmin-1 (ISM1) was initially thought to be a brain secretory factor, but with the development of technical means of research and the refinement of animal models, numerous studies have shown that this molecule is expressed in multiple tissues, suggesting that it may have multiple biological functions. As a factor that regulates growth and development, ISM1 is expressed in different animals with spatial and temporal variability and can coordinate the normal development of multiple organs. Recent studies have found that under the dependence of a non-insulin pathway, ISM1 can lower blood glucose, inhibit insulin-regulated lipid synthesis, promote protein synthesis, and affect the body's glucolipid and protein metabolism. In addition, ISM1 plays an important role in cancer development by promoting apoptosis and anti-angiogenesis, and by regulating multiple inflammatory pathways to influence the body's immune response. The purpose of this paper is to summarize relevant research results from recent years and to describe the key features of the biological functions of ISM1. We aimed to provide a theoretical basis for the study of ISM1 related diseases, and potential therapeutic strategies. The main biological functions of ISM1. Current studies on the biological functions of ISM1 focus on growth and development, metabolism, and anticancer treatment. During embryonic development, ISM1 is dynamically expressed in the zebrafish, African clawed frog, chick, mouse, and human, is associated with craniofacial malformations, abnormal heart localization, and hematopoietic dysfunction. ISM1 plays an important role in regulating glucose metabolism, lipid metabolism, and protein metabolism in the body. ISM1 affects cancer development by regulating cellular autophagy, angiogenesis, and the immune microenvironment.

Cleft Lip and Palate in Four Full-Sib Puppies from a Single Litter of Staffordshire Bull Terrier Dogs: An Anatomical and Genetic Study

Cleft lip and palate (CLP) is a well-known congenital defect in dogs, characterized by abnormal communication between the oral and nasal cavities. Its incidence rate is high and affects all dog breeds. The etiology of CLP is thought to be multifactorial, caused by both genetic and environmental factors. In this study, four puppies out of seven from a single litter of Staffordshire Bull Terrier dogs with craniofacial abnormalities were anatomically and genetically examined. Classical anatomical preparation, dyed-latex-injection of the arterial vessels, and cone-beam computed tomography were used. The puppies showed variations in their observable abnormalities: three of them had a complete cleft of the palate on both sides, while one puppy had a cleft on the right side only. Cytogenetic analysis showed a normal diploid chromosome number (2n = 78,XX or 78,XY) in the studied animals. Known genomic variants of CLP were examined in the ADAMTS20, DLX6, and MYH3 genes, but no mutations were identified. Further studies are needed to identify the breed-specific genetic variants associated with canine CLP.

Bifid Uvula-An Enigma

Facial development involves an intricate regulatory mechanism that accounts for numerous craniofacial abnormalities, common being orofacial clefts. Although cleft in the secondary palate accounts for one-third of orofacial clefts stills remains an under-researched domain. Hence, in this work, the authors put forth two non-syndromic, asymptomatic cleft uvulae reported among bimodal male patients of the Indian-Asiatic population who came up for dental screening. Most of the time, isolated/asymptomatic cleft uvula patients will be reluctant to further investigations and treatment. Although bifid uvula looks benign in most patients, it may sometimes be associated with catastrophic complications. To conclude, whenever bifid uvula is an incidental finding, it is the responsibility of the healthcare worker to plan a thorough patient workup as a primary preventive measure to rule out any complications whenever feasible. It can help us overcome many future unforeseen sequelae and emergency management due to bifid uvula.

Characterization of SHH, SOX3, WNT3A and WNT9B Proteins in Human Non-Syndromic Cleft Lip and Palate Tissue

Orofacial clefts have been associated with specific cleft candidate genes which encode regulatory proteins required for orofacial region development. Cleft candidate genes encode proteins involved with the cleft morphopathogenesis process, but their exact interactions and roles are relatively unclear in human cleft tissue. This study evaluates the presence and correlations of Sonic Hedgehog (SHH), SRY-Box Transcription Factor 3 (SOX3), Wingless-type Family Member 3A (WNT3A) and 9B (WNT9B) protein containing cells in different cleft tissue. Non-syndromic cleft-affected tissue was subdivided into three groups-unilateral cleft lip (UCL) (n = 36), bilateral cleft lip (BCL) (n = 13), cleft palate (CP) (n = 26). Control tissue was obtained from five individuals. Immunohistochemistry was implemented. The semi-quantitative method was used. Non-parametric statistical methods were applied. A significant decrease in SHH was found in BCL and CP tissue. SOX3, WNT3A and WNT9B had a significant decrease in all clefts. Statistically significant correlations were found. The significant decrease in SHH could be associated with BCL and CP pathogenesis. SOX3, WNT3A and WNT9B could have morphopathogenetic involvement in UCL, BCL, and CP. Similar correlations imply the presence of similar pathogenetic mechanisms in different cleft variations.

Single cell sequencing of the mouse anterior palate reveals mesenchymal heterogeneity

BACKGROUND

Cleft palate is one of the most prevalent birth defects. Mice are useful for studying palate development because of their morphological and genetic similarities to humans. In mice, palate development occurs between embryonic days (E)11.5 to 15.5. Single cell transcriptional profiles of palate cell populations have been a valuable resource for the craniofacial research community, but we lack a single cell transcriptional profile for anterior palate at E13.5, at the transition from proliferation to shelf elevation.

RESULTS

A detailed single cell RNA sequencing analysis reveals heterogeneity in expression profiles of the cell populations of the E13.5 anterior palate. Hybridization chain reaction RNA fluorescent in situ hybridization (HCR RNA FISH) reveals epithelial populations segregate into layers. Mesenchymal populations spatially segregate into four domains. One of these mesenchymal populations expresses ligands and receptors distinct from the rest of the mesenchyme, suggesting that these cells have a unique function. RNA velocity analysis shows two terminal cell states that contribute to either the proximal or distal palatal regions emerge from a single progenitor pool.

CONCLUSION

This single cell resolution expression data and detailed analysis from E13.5 anterior palate provides a powerful resource for mechanistic insight into secondary palate morphogenesis for the craniofacial research community.

Identification of Novel Risk Variants of Non-Syndromic Cleft Palate by Targeted Gene Panel Sequencing

Non-syndromic cleft palate (ns-CP) has a genetically heterogeneous aetiology. Numerous studies have suggested a crucial role of rare coding variants in characterizing the unrevealed component of genetic variation in ns-CP called the "missing heritability". Therefore, this study aimed to detect low-frequency variants that are implicated in ns-CP aetiology in the Polish population. For this purpose, coding regions of 423 genes associated with orofacial cleft anomalies and/or involved with facial development were screened in 38 ns-CP patients using the next-generation sequencing technology. After multistage selection and prioritisation, eight novel and four known rare variants that may influence an individual's risk of ns-CP were identified. Among detected alternations, seven were located in novel candidate genes for ns-CP, including COL17A1 (c.2435-1G>A), DLG1 (c.1586G>C, p.Glu562Asp), NHS (c.568G>C, p.Val190Leu-de novo variant), NOTCH2 (c.1997A>G, p.Tyr666Cys), TBX18 (c.647A>T, p.His225Leu), VAX1 (c.400G>A, p.Ala134Thr) and WNT5B (c.716G>T, p.Arg239Leu). The remaining risk variants were identified within genes previously linked to ns-CP, confirming their contribution to this anomaly. This list included ARHGAP29 (c.1706G>A, p.Arg569Gln), FLNB (c.3605A>G, Tyr1202Cys), IRF6 (224A>G, p.Asp75Gly-de novo variant), LRP6 (c.481C>A, p.Pro161Thr) and TP63 (c.353A>T, p.Asn118Ile). In summary, this study provides further insights into the genetic components contributing to ns-CP aetiology and identifies novel susceptibility genes for this craniofacial anomaly.

Maternal stress as a risk factor for non-syndromic orofacial clefts: Systematic review and meta-analysis

Background

Non-syndromic orofacial clefts (NSOFC) are among the most common congenital malformations. Several studies have investigated the association between stress and NSOFC; however, they have reported different and heterogeneous results. Therefore, this systematic review was conducted to investigate the association between maternal periconceptional stress and non-syndromic orofacial clefts in infants.The research question was "Is maternal periconceptional stress an etiological factor for non-syndromic orofacial clefts in infants"?

Methods

Search strategy, inclusion/exclusion criteria, and data extraction from studies reporting periconceptional maternal exposure to stress and NSOFC were implemented without language restrictions. The risks of bias in the identified studies was assessed, and this information was used in the sensitivity analyses to explain heterogeneity. A meta-analysis of the extracted data was performed.

Results

Twelve eligible studies were included. Forest plot for meta-analysis of the association between maternal periconceptional exposure to stress and NSOFC among studies with adjustment for potential confounders showed a statistically significant association with an increased risk of NSOFC (odds ratio [OR]:1.17; P = 0.03), which was apparent for both cleft lip with and without palate (OR:2.07; P = 0.007) and cleft palate (OR:1.72; P = 0.003). There was a substantial heterogeneity between studies, which improved when analyzing only studies that were adjusted for potential confounders.

Conclusion

Based on the currently available evidence, maternal exposure to periconceptional stress could be considered a risk factor for NSOFCs. Therefore, we strongly recommend research investigating the effect of stress caused by the coronavirus disease-2019 pandemic on the incidence of clefts.

Genetic Risk Assessment of Nonsyndromic Cleft Lip with or without Cleft Palate by Linking Genetic Networks and Deep Learning Models

Recent deep learning algorithms have further improved risk classification capabilities. However, an appropriate feature selection method is required to overcome dimensionality issues in population-based genetic studies. In this Korean case-control study of nonsyndromic cleft lip with or without cleft palate (NSCL/P), we compared the predictive performance of models that were developed by using the genetic-algorithm-optimized neural networks ensemble (GANNE) technique with those models that were generated by eight conventional risk classification methods, including polygenic risk score (PRS), random forest (RF), support vector machine (SVM), extreme gradient boosting (XGBoost), and deep-learning-based artificial neural network (ANN). GANNE, which is capable of automatic input SNP selection, exhibited the highest predictive power, especially in the 10-SNP model (AUC of 88.2%), thus improving the AUC by 23% and 17% compared to PRS and ANN, respectively. Genes mapped with input SNPs that were selected by using a genetic algorithm (GA) were functionally validated for risks of developing NSCL/P in gene ontology and protein-protein interaction (PPI) network analyses. The IRF6 gene, which is most frequently selected via GA, was also a major hub gene in the PPI network. Genes such as RUNX2, MTHFR, PVRL1, TGFB3, and TBX22 significantly contributed to predicting NSCL/P risk. GANNE is an efficient disease risk classification method using a minimum optimal set of SNPs; however, further validation studies are needed to ensure the clinical utility of the model for predicting NSCL/P risk.

Ultra-Rare Variants Identify Biological Pathways and Candidate Genes in the Pathobiology of Non-Syndromic Cleft Palate Only

In recent decades, many efforts have been made to elucidate the genetic causes of non-syndromic cleft palate (nsCPO), a complex congenital disease caused by the interaction of several genetic and environmental factors. Since genome-wide association studies have evidenced a minor contribution of common polymorphisms in nsCPO inheritance, we used whole exome sequencing data to explore the role of ultra-rare variants in this study. In a cohort of 35 nsCPO cases and 38 controls, we performed a gene set enrichment analysis (GSEA) and a hypergeometric test for assessing significant overlap between genes implicated in nsCPO pathobiology and genes enriched in ultra-rare variants in our cohort. GSEA highlighted an enrichment of ultra-rare variants in genes principally belonging to cytoskeletal protein binding pathway (Probability Density Function corrected p-value = 1.57 × 10^-4); protein-containing complex binding pathway (p-value = 1.06 × 10^-2); cell adhesion molecule binding pathway (p-value = 1.24 × 10^-2); ECM-receptor interaction pathway (p-value = 1.69 × 10^-2); and in the Integrin signaling pathway (p-value = 1.28 × 10^-2). Two genes implicated in nsCPO pathobiology, namely COL2A1 and GLI3, ranked among the genes (n = 34) with nominal enrichment in the ultra-rare variant collapsing analysis (Fisher's exact test p-value < 0.05). These genes were also part of an independent list of genes highly relevant to nsCPO biology (n = 25). Significant overlap between the two sets of genes (hypergeometric test p-value = 5.86 × 10^-3) indicated that enriched genes are likely to be implicated in physiological palate development and/or the pathological processes of oral clefting. In conclusion, ultra-rare variants collectively impinge on biological pathways crucial to nsCPO pathobiology and point to candidate genes that may contribute to the individual risk of disease. Sequencing can be an effective approach to identify candidate genes and pathways for nsCPO.

The Risk of Orofacial Cleft Lip/Palate Due to Maternal Ambient Air Pollution Exposure: A Call for Further Research in South Africa

Background

Despite being underreported, orofacial cleft lip/palate (CLP) remains in the top five of South Africa's most common congenital disorders. Maternal air pollution exposure has been associated with CLP in neonates. South Africa has high air pollution levels due to domestic burning practices, coal-fired power plants, mining, industry, and traffic pollution, among other sources. We investigated air pollutant levels in geographic locations of CLP cases.

Methods

In a retrospective case series study (2006-2020) from a combined dataset by a Gauteng surgeon and South African Operation Smile, the maternal address at pregnancy was obtained for 2,515 CLP cases. Data from the South African Air Quality Information System was used to calculate annual averages of particulate matter (PM) concentrations of particles < 10 µm (PM₁₀) and < 2.5 µm (PM_2.5). Correlation analysis determined the relationship between average PM_2.5/PM₁₀ concentrations and CLP birth prevalence. Hotspot analysis was done using the Average Nearest Neighbor tool in ArcGIS.

Results

Correlation analysis showed an increasing trend of CLP birth prevalence to PM₁₀ (CC = 0.61, 95% CI = 0.38-0.77, p < 0.001) and PM_2.5 (CC = 0.63, 95% CI = 0.42-0.77, p < 0.001). Hot spot analysis revealed that areas with higher concentrations of PM₁₀ and PM_2.5 had a higher proclivity for maternal residence (z-score = -68.2, p < 0.001). CLP birth prevalence hotspot clusters were identified in district municipalities in the provinces of Gauteng, Limpopo, North-West, Mpumalanga, and Free State. KwaZulu-Natal and Eastern Cape had lower PM₁₀ and PM_2.5 concentrations and were cold spot clusters.

Conclusions

Maternal exposure to air pollution is known to impact the fetal environment and increase CLP risk. We discovered enough evidence of an effect to warrant further investigation. We advocate for a concerted effort by the government, physicians, researchers, non-government organizations working with CLP patients, and others to collect quality data on all maternal information and pollutant levels in all provinces of South Africa. Collaboration and data sharing for additional research will help us better understand the impact of air pollution on CLP in South Africa.

Current Concepts and Challenges in the Treatment of Cleft Lip and Palate Patients-A Comprehensive Review

Cleft lip and cleft palate has one of the highest incidences in the malformations of the oral cavity, that varies between populations. The background underlying the issue of cleft lip and palate is multifactorial and greatly depends on the genetic factors and environmental factors. The aim of this nonsystematic narrative review is to present the cleft palate and or lip pediatric population as target for interdisciplinary treatment. The purpose of this narrative review is to sum up the modern knowledge on the treatment of patients with clefts, as well as to highlight the importance of the great need for cooperation between different dental specialists along with medical professionals such as oral surgeons, prosthodontists, orthodontists along with medical professions such as pediatricians, speech therapists and phoniatrics, and laryngologist.

mir152 hypomethylation as a mechanism for non-syndromic cleft lip and palate

Non-syndromic cleft lip with or without cleft palate (NSCLP), the most common human craniofacial malformation, is a complex disorder given its genetic heterogeneity and multifactorial component revealed by genetic, epidemiological, and epigenetic findings. Epigenetic variations associated with NSCLP have been identified; however, functional investigation has been limited. Here, we combined a reanalysis of NSCLP methylome data with genetic analysis and used both in vitro and in vivo approaches to dissect the functional effects of epigenetic changes. We found a region in mir152 that is frequently hypomethylated in NSCLP cohorts (21-26%), leading to mir152 overexpression. mir152 overexpression in human neural crest cells led to downregulation of spliceosomal, ribosomal, and adherens junction genes. In vivo analysis using zebrafish embryos revealed that mir152 upregulation leads to craniofacial cartilage impairment. Also, we suggest that zebrafish embryonic hypoxia leads to mir152 upregulation combined with mir152 hypomethylation and also analogous palatal alterations. We therefore propose that mir152 hypomethylation, potentially induced by hypoxia in early development, is a novel and frequent predisposing factor to NSCLP.

Time series analysis on association between ambient air pollutants and orofacial clefts during pregnancy in Lanzhou, China

Current studies on air pollutant exposure during pregnancy and orofacial clefts (OFCs) have inconsistent results, and few studies have investigated refined susceptible windows for OFCs. We aim to estimate association between air pollution and OFCs during the first trimester of pregnancy and identify specific susceptible windows. Birth data was obtained from Birth Defects Surveillance Network in Lanzhou from 2014 to 2019. Air pollution data and temperature data were obtained from ambient air monitoring stations and China Meteorological Data Network, respectively. A distribution lag nonlinear model (DLNM) was applied to estimate weekly-exposure-lag-response association between air pollutant levels and OFCs. The study included 320,787 perinatal infants from 2014 to 2019, of which 685 (2.14‰) were OFCs. The results demonstrated that exposure of pregnant women to aerodynamic diameter ≤ 10 μm (PM₁₀) at lag 4-5 weeks was significantly associated with the risk of OFCs, with the greatest impact at the lag 4 week (RR = 1.029, 95% CI = 1.001-1.057). Exposure to sulfur dioxide (SO₂) at lag 2-4 weeks was significantly associated with the risk of OFCs, with the greatest impact at the lag 3 week (RR = 1.096, 95% CI = 1.041-1.177). This study provides further evidence that exposure to air pollution increases the risk of OFCs in the first trimester of pregnancy.

Cleft Palate in Apert Syndrome

Apert syndrome is a rare genetic disorder characterized by craniosynostosis, midface retrusion, and limb anomalies. Cleft palate occurs in a subset of Apert syndrome patients. Although the genetic causes underlying Apert syndrome have been identified, the downstream signaling pathways and cellular mechanisms responsible for cleft palate are still elusive. To find clues for the pathogenic mechanisms of palatal defects in Apert syndrome, we review the clinical characteristics of the palate in cases of Apert syndrome, the palatal phenotypes in mouse models, and the potential signaling mechanisms involved in palatal defects. In Apert syndrome patients, cleft of the soft palate is more frequent than of the hard palate. The length of the hard palate is decreased. Cleft palate is associated most commonly with the S252W variant of FGFR2. In addition to cleft palate, high-arched palate, lateral palatal swelling, or bifid uvula are common in Apert syndrome patients. Mouse models of Apert syndrome display palatal defects, providing valuable tools to understand the underlying mechanisms. The mutations in FGFR2 causing Apert syndrome may change a signaling network in epithelial–mesenchymal interactions during palatogenesis. Understanding the pathogenic mechanisms of palatal defects in Apert syndrome may shed light on potential novel therapeutic solutions.

Immunohistochemical Evaluation of BARX1, DLX4, FOXE1, HOXB3, and MSX2 in Nonsyndromic Cleft Affected Tissue

Background

Nonsyndromic craniofacial clefts are relatively common congenital malformations which could create a significant negative effect on the health status and life quality of affected individuals within the pediatric population. Multiple cleft candidate genes and their coded proteins have been described with their possible involvement during cleft formation. Some of these proteins like Homeobox Protein BarH-like 1 (BARX1), Distal-Less Homeobox 4 (DLX4), Forkhead Box E1 (FOXE1), Homeobox Protein Hox-B3 (HOXB3), and Muscle Segment Homeobox 2 (MSX2) have been associated with the formation of craniofacial clefts. Understanding the pathogenetic mechanisms of nonsyndromic craniofacial cleft formation could provide a better knowledge in cleft management and could be a possible basis for development and improvement of cleft treatment options. This study investigates the presence of BARX1, DLX4, FOXE1, HOXB3, and MSX2 positive cells by using immunohistochemistry in different types of cleft-affected tissue while determining their possible connection with cleft pathogenesis process.

Materials and Methods

Craniofacial cleft tissue material was obtained during cleft-correcting surgery from patients with nonsyndromic craniofacial cleft diagnosis. Tissue material was gathered from patients who had unilateral cleft lip (n=36), bilateral cleft lip (n=13), and cleft palate (n=26). Control group (n=7) tissue material was received from individuals without any craniofacial clefts. The number of factor positive cells in the control group and patient group tissue was evaluated by using the semiquantitative counting method. Data was evaluated with the use of nonparametric statistical methods.

Results

Statistically significant differences were identified between the number of BARX1, FOXE1, HOXB3, and MSX2-containing cells in controls and cleft patient groups but no statistically significant difference was found for DLX4. Statistically significant correlations between the evaluated factors were also notified in cleft patient groups.

Conclusions

HOXB3 could be more associated with morphopathogenesis of unilateral cleft lip during postnatal course of the disorder. FOXE1 and BARX1 could be involved with both unilateral and bilateral cleft lip morphopathogenesis. The persistence of MSX2 in all evaluated cleft types could indicate its possible interaction within multiple cleft types. DLX4 most likely is not involved with postnatal cleft morphopathogenesis process.

Time-series expression profiles of mRNAs and lncRNAs during mammalian palatogenesis

OBJECTIVES

Mammalian palatogenesis is a highly regulated morphogenetic process to form the intact roof of the oral cavity. Long noncoding RNAs (lncRNAs) and mRNAs participate in numerous biological and pathological processes, but their roles in palatal development and causing orofacial clefts (OFC) remain to be clarified.

METHODS

Palatal tissues were separated from ICR mouse embryos at four stages (E10.5, E13.5, E15, and E17). Then, RNA sequencing (RNA-seq) was used. Various analyses were performed to explore the results. Finally, hub genes were validated via qPCR and in situ hybridization.

RESULTS

Starting from E10.5, the expression of cell adhesion genes escalated in the following stages. Cilium assembly and ossification genes were both upregulated at E15 compared with E13.5. Besides, the expression of cilium assembly genes was also increased at E17 compared with E15. Expression patterns of three lncRNAs (H19, Malat1, and Miat) and four mRNAs (Cdh1, Irf6, Grhl3, Efnb1) detected in RNA-seq were validated.

CONCLUSIONS

This study provides a time-series expression landscape of mRNAs and lncRNAs during palatogenesis, which highlights the importance of processes such as cell adhesion and ossification. Our results will facilitate a deeper understanding of the complexity of gene expression and regulation during palatogenesis.

Target sequencing reveals the association between variants in VAX1 and NSCL/P in Chinese population

OBJECTIVE

A significant genetic association between rs7078160 in VAX1 and NSCL/P has been established through genome-wide association studies (GWAS), and we previously replicated the association in the Chinese population. The critical issue in the post-GWAS era is to identify functional variations that have a real impact on disease in the susceptible regions highlighted by GWAS. This study aimed to elucidate functional variants in VAX1 fully.

MATERIALS AND METHODS

Firstly, target sequencing was performed on 159 NSCL/P patients, followed by association analysis to discover disease-associated single nucleotide polymorphisms (SNPs); we then replicated the findings using a larger sample (1626 cases, 2255 controls) and investigated how candidate SNPs affect disease occurrence using extensive annotation databases. Additionally, we compared the genetic profiles of NSCL/P subtypes.

RESULTS

In this study, 6 SNPs in VAX1 were identified to be associated with NSCL/P in the Western Han Chinese population. Five of them were predicted to influence transcriptional factor biding ability and were expression quantitative trait loci (eQTLs) of nearby genes in multiple tissues.

CONCLUSION

The previously reported association between rs7078160 and NSCL/P was successfully replicated. Moreover, our findings firstly revealed that 5 SNPs in VAX1 are associated with NSCL/P in the Western Han Chinese population.

Analysis of Gene-Environment Interactions Related to Developmental Disorders

Various genetic and environmental factors are associated with developmental disorders (DDs). It has been suggested that interaction between genetic and environmental factors (G × E) is involved in the etiology of DDs. There are two major approaches to analyze the interaction: genome-wide and candidate gene-based approaches. In this mini-review, we demonstrate how these approaches can be applied to reveal the G × E related to DDs focusing on zebrafish and mouse models. We also discuss novel approaches to analyze the G × E associated with DDs.

Two rare variants reveal the significance of Grainyhead‐like 3 Arginine 391 underlying non‐syndromic cleft palate only

OBJECTIVES

Non-syndromic cleft palate only (NSCPO) is one of the most common craniofacial birth defects with largely undetermined genetic etiology. It has been established that Grainyhead-like 3 (GRHL3) plays an essential role in the pathogenesis of NSCPO. This study aimed to identify and verify the first-reported GRHL3 variant underlying NSCPO among the Chinese cohort.

METHODS

We performed whole-exome sequencing (WES) on a Chinese NSCPO patient and identified a rare variant of GRHL3 (p.Arg391His). A validated deleterious variant p.Arg391Cys was introduced as a positive control. Zebrafish embryos injection, reporter assays, live-cell imaging, and RNA sequencing were conducted to test the pathogenicity of the variants.

RESULTS

Zebrafish embryos microinjection demonstrated that overexpression of the variants could disrupt the normal development of zebrafish embryos. Reporter assays showed that Arg391His disturbed transcriptional activity of GRHL3 and exerted a dominant-negative effect. Interestingly, Arg391His and Arg391Cys displayed distinct nuclear localization patterns from that of wild-type GRHL3 in live-cell imaging. Bulk RNA sequencing suggested that the two variants changed the pattern of gene expression.

CONCLUSIONS

In aggregate, this study identified and characterized a rare GRHL3 variant in NSCPO, revealing the critical role of Arginine 391 in GRHL3. Our findings will help facilitate understanding and genetic counseling of NSCPO.

Concepts in Multifactorial Etiology of Developmental Disorders: Gene-Gene and Gene-Environment Interactions in Holoprosencephaly

Many common developmental disorders are thought to arise from a complex set of genetic and environmental risk factors. These factors interact with each other to affect the strength and duration of key developmental signaling pathways, thereby increasing the possibility that they fail to achieve the thresholds required for normal embryonic patterning. One such disorder, holoprosencephaly (HPE), serves as a useful model system in understanding various forms of multifactorial etiology. Genomic analysis of HPE cases, epidemiology, and mechanistic studies of animal models have illuminated multiple potential ways that risk factors interact to produce adverse developmental outcomes. Among these are: 1) interactions between driver and modifier genes; 2) oligogenic inheritance, wherein each parent provides predisposing variants in one or multiple distinct loci; 3) interactions between genetic susceptibilities and environmental risk factors that may be insufficient on their own; and 4) interactions of multiple genetic variants with multiple non-genetic risk factors. These studies combine to provide concepts that illuminate HPE and are also applicable to additional disorders with complex etiology, including neural tube defects, congenital heart defects, and oro-facial clefting.